1. Technical Field
This disclosure relates to wireless communication devices, such as cell phones, laptops, and PDAs, and to radio network controllers which allow these wireless devices communicate to obtain data services.
2. Description of Related Art
Wireless communication devices, such as cell phones, laptops, and PDAs, may communicate with one or more data networks for the purpose of transmitting and/or receiving data. The data may include one or more web pages, images, streaming media, games, ring tones, and/or other information.
To facilitate and to regulate these communications, a mobile communication device may send a request to a radio network controller (RNC) for a data service relating to the data network. In turn, the radio network controller may communicate with an authentication, authorization, and accounting (AAA) server to authenticate the mobile communication device and/or to verify its authorization to access the data network. Once approved, the radio network controller may serve as a gateway between the mobile communication device and the data network.
The radio network controller may experience delays when performing these tasks. These may be caused, for example, by the near simultaneous receipt of requests for data services from a large number of mobile communication devices. Delays may in addition or instead be caused by delays in responses from the authentication, authorization, and accounting server, which may similarly be caused by the server receiving a large number of requests from radio network controllers.
When a mobile communication device fails to receive a timely response to a request to the radio network controller for data services, the mobile communication device may resend the request. If the resent request does not receive a timely response, the request may again be resent, and so forth. This may cause the radio network controller to queue multiple requests for the very same service, which may substantially add to the load on the controller.
Similarly, when a radio network controller does not receive a timely response to a request which it delivers to an authentication, authorization, and accounting server, the radio network controller may resend the request to the server. If the resent request does not receive a timely response, the request may again be resent, and so forth. This may cause the server to queue multiple requests for the very same service, which may substantially add to the load on the server.
The continued resending of requests by mobile communication devices may therefore cause a cascading delay, which may ultimately lead to a denial of service. This may occur even though the problem which originally caused the delay, such as a delay in receiving responses from an authentication, authorization, and accounting server, has been remedied.
To help alleviate this problem, mobile communication devices have been programmed to stop sending requests for data services to radio network controllers after a predetermined number of tries have failed to be successful. However, the period of self-imposed delay may be more than what is needed to allow for a recovery, causing an unnecessarily long delay in obtaining access to desired data. In other cases, the period of self-imposed delay may not be sufficient to enable the radio network controller and/or its associated, authentication, authorization, and accounting server to recuperate, in which case the resent requests may continue to contribute to an overload.